Which city can claim the title “biggest city in the
world” is somewhat controversial. Some city-like regions are technically
separated in to smaller communities; others include suburbs, so which one is
it? In order to compare sizes it is necessary to find a common denominator. We
do actually have a perfect one. The technical term is: metropolitan area.

The biggest city in the world
based on this term is Tokyo in Japan. Approximately 34 million people
live in the metropolitan area of Tokyo.

Most rankings name Mexico City
as the second biggest city. A staggering 25 million people live in the
Mexican capital. Other rankings have Sudogwon (Seoul) as the number two.
It depends a little on how you define it. Here we chose Mexico. Then
there are a number of cities with over 15 million people; namely Bombay,
Jakarta, Shanghai, Sao Paulo, Manila and New York.

Another 25 cities worldwide have
a population of about 10 million people, 270 qualify as megacity (at
least 1 million inhabitants).

It is estimated that Tokyo won’t
be the biggest city in the world for much longer. The Japanese
population in general is not growing anymore (rather the opposite) and
there is little to no immigration. Tokyo most likely will be affected by
the decline. In 10 to 20 years it will probably lose the title to Mexico
City. That said; Bombay, Jakarta and Kairo are growing rapidly. In China
we can see an ambition to develop gigantic metropolitan areas. Chinese
authorities want to turn the area around Shenzen into the biggest
metropolitan area in the world with an estimated population of 42
million people. The race for the biggest city in the world is very much
open one could say.